1. Technical Field
The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject a liquid from a nozzle, and, in particular, relates to an ink jet recording head and an ink jet recording apparatus that eject ink as a liquid.
2. Related Art
Representative examples of liquid ejecting heads that eject a liquid include ink jet recording heads that eject ink. An ink jet recording head equipped with a plurality of head main bodies that eject ink from nozzles and a common liquid introduction member (corresponds to a storage member) that supplies ink to each head main body from a liquid storage member in which the ink is stored fixed to the plurality of head main bodies is proposed (for example, refer to JP-A-2005-225219).
The ink jet recording head includes a circuit substrate connected to a pressure generating unit such as a piezoelectric actuator by which pressure changes are generated in a pressure generating chamber of the head main body (for example, refer to JP-A-2006-272885).
In the ink jet recording head in JP-A-2006-272885, the circuit substrate is held between a case that holds the flow channel unit (corresponds to the head main body) and an introduction needle unit.
However, when ink attaches to the circuit substrate, short circuits and the like of the wiring provided in the circuit substrate occur, and operation defects or failures occur.
Therefore, an ink jet recording head in which the circuit substrate is sealed in a plastic case having an opening large enough for the connection wiring connected to the circuit substrate to pass through is proposed (for example, refer to JP-A-2003-11383).
An ink jet recording head in which the circuit substrate is protected from ink by an insulating film, an adhesive or the like is proposed (for example, refer to JP-A-2009-978).
However, in a case where a butyl rubber having resistance to a solvent-based ink that includes a solvent is used in a wiping blade that wipes the liquid ejecting surface or a tube that supplies or discharges ink, a problem arises where sulfur added to the butyl rubber by the vulcanization process is generated as an outgas, corrosion products (sulfides) attach to the wiring by the sulfur reacting to silver or copper included in the wiring, and wirings adjacent to one another short circuit.
A problem arises where sulfur included in the insulating material such as a resist that covers the wiring by the solvent included in the solvent-based ink is generated as an out gas, and corrosion products (sulfides) attach to the wiring by the sulfur reacting the silver or copper included in the wiring.
A further problem arises where the copper, silver or the like at the original location is lost, and a cavity is formed, thereby causing a disconnection, when the corrosion products (sulfides) are generated.
In particular, when the wiring connected to the pressure generating unit short circuits due to the sulfide, a plurality of pressure generating units connected to the shorted wiring are driven at the same time, and ink is ejected at the same time. An ink ejection defect arises when the wiring is disconnected due to the sulfide.
Such a problem is similarly present not only in an ink jet recording head, but also in liquid ejecting heads that eject liquids other than ink.